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Sunday, January 1, 2017

Notwithstanding the overwhelming evidence that an excess of
calorie intake per se, irrespective
of the source of calories, causes obesity, there remains a populist and a policy
view that sugar, rather than fat is the primary culprit. Although the
biological argument that not all calories are equal and that carbohydrate
calories are more fattening has been debunked by sound experimental evidence[1],
the case moves more to appetite as the causative factor. Since people don’t eat
what they don’t like, an understanding of the “liking” of particular foods
becomes important.

To study this phenomenon, two approaches are possible. One is
to use a ‘cross sectional’ approach which seeks to compare obese persons and
lean persons for their food preferences at a single moment in time. The problem
here is that the obese persons may have acquired a view of what putatively
‘causes’ obesity and in so doing, they may bias their response to any study
questionnaires. Thus obese subjects at a given point in time might express a
lower liking for sugar-sweetened beverages compared to diet beverages because
that is what they are conditioned by society to believe. Moreover, obese
subjects may in fact use sugar free beverages to manage their weight. The
alternative to this approach is to complete a ‘prospective’ study in which
people’s likings for food are measured at a single point in time and the group
subsequently followed over several years to see who gets obese and who stays
slim. That way, the presence of obesity is independent of the answers to the
original questionnaire.

A recent paper from the French research consortium
“NutriSanté” has examined the effect of liking for fat, sugar and salt on
subsequent development of obesity[2].
The NutriSanté study is an internet-based study, initiated in 2009, with a
current enrolment of some 65,683 volunteers. Data is gathered at the point of
recruitment on many aspects of health such as diet, physical activity, weight,
smoking and alcohol habits, weight management and so on and is repeated
annually. Each month, volunteers are
invited to complete questionnaires related among other things to food
behaviour. The questionnaire covered
salt (11 questions) and sweet (21 questions) tastes plus preferences of
fat-and-salt (31 questions) and fat and sweet sensations (20 items). Some 49,066 subjects agreed to answer these
questions. However, when the data were cleaned up to ensure that all
respondents had completed every aspect of the overall NutriSanté study, there
were full data on 24,776 subjects.

In the 4 years of follow up, 24,112 subjects remained non-obese
while 664 subjects became obese. The key sensory findings are thus:

Sensory liking scores

Non-obese subjects

Obese subjects

Statistical conclusions

Liking for fat

3.79

4.03

Highly
different

Liking for sweet

3.73

3.66

No
difference

Liking for salt

3.77

3.93

Highly
different

Those who gained weight had a higher preference for fat and
salt but not for sugar.Another approach
to the data analysis is to look across the “liking” score data and to divide
subjects according to their ranking, starting at the “low liking” (lowest
quarter or ‘quartile’) right up to the “highest liking”(highest quartile). These data are controlled
statistically for all known confounding variables.

Statistical difference in risk of
developing obesity between lowest and highest quartiles of “liking”

Men

Women

Fat liking

Yes,
up 85%

Yes,
up 49%

Fat + salt liking

Yes,
up 106%

No

Fat + sweet liking

No

Yes,
up 37%

Sweet liking

Yes,
down 59%

No

Natural sweetness liking

No

Yes,
down 69%

The authors also looked at baseline food intake (as opposed
to liking) and observed no association between sugary food intake and obesity.
Indeed, the evidence was that those who did not develop obesity had higher
sugar intakes at baseline. The results are summarised below.

Food group intake g/d

Non-obese subjects

Obese subjects

Statistical conclusions

Fruits

279

234

Highly
different

Meat

45

57

Highly
different

Processed meat

3.77

3.93

Highly
different

Milk and yogurts

169

192

Highly
different

Cheese

38

36

Not
different

Oil

9.3

8.1

Highly
different

Whole grain products

36

28

Highly
different

Sugar and products

24

19

Highly
different

Fatty sweet products

69

65

Not
different

Sugar-sweetened soft drinks

39

41

Not
different

The authors conclude thus: “This prospective study reinforced results from cross sectional
studies, by highlighting that fat liking was prospectively associated with an
increased risk of obesity and diet appeared to substantially explain this
relationship. Results have also shown that sweet liking is associated with a
decreased risk of obesity, and there is no significant association between salt
liking and obesity risk”.

Once again, we have a fully public funded comprehensive and prospective
study from a highly reputable group, with the study suitably powered for
optimal statistical analysis, which challenges conventional wisdom. It will be
ignored but, you see, it won’t go away and one day, when the false gods of the
demonic sugar sect are reduced to clay, these papers will come back to haunt
the high priests of public health nutrition. I wanna be there!!!

By the way, the blog stands now at 231,325 views. Thank you all and a happy New Year to all of you.

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"Ever seen a fat fox ~ Human obesity explored"

About Me

I graduated from University College Dublin in 1971 with an Masters in Agricultural Chemistry, took a PhD at Sydney University in 1976 and joined the University of Southampton Medical School as a lecturer in human nutrition in 1977. In 1984 I returned to Ireland to take up a post at the Department of Clinical Medicine Trinity College Dublin and was appointed as professor of human nutrition. In 2006 I left Trinity and moved to University College Dublin as Director of the UCD Institute of Food and Health. I am a former President of the Nutrition Society and I've served on several EU and UN committees on nutrition and Health. I have published over 350+ peer reviewed scientific papers in Public Health Nutrition and Molecular Nutrition and am principal investigator on several national and EU projects (www.ucd.ie/jingo; www.food4me.org). My popular books are "Something to chew on ~ challenging controversies in human nutrition" and "Ever seen a fat fox: human obesity explored"